There is a significant need to develop approaches for evaluating the biological impact of new and emerging tobacco-related products in order to identify those that are most likely to cause serious risks to human health. Our proposal is based on the field of injury paradigm in which 1) inhaled toxins such as tobacco smoke alter gene-expression in epithelial cells lining the entire respiratory tract and 2) measuring these alteratios in readily accessible upper airway epithelial cells provides insight into the physiological effect f that exposure. We have previously used this concept to identify physiologic responses to tobacco smoke exposure and develop a bronchial airway gene-expression signature that is an early detection biomarker for lung cancer. The overall goals of this proposal are to 1) demonstrate the utility of airway epithelium profiling to identify physiologic responses to other tobacco products and 2) establish in vitro exposure systems that can accurately model physiological exposures and rapidly assess the potential carcinogenicity of tobacco-related products in vitro. We have focused this proposal on E-cigarettes (ECIGS), an emerging FDA-regulated tobacco-related product, due to: 1) their growing popularity, 2) their chemical dissimilarity to tobacco cigarettes (TCIGS), and 3) the absence of data regarding their potential health effects. We propose three simultaneous studies focused around identifying physiologic and cellular responses of airway epithelium to ECIGS. The first two studies involve gene-expression profiling in bronchial and nasal epithelial brushings from ECIGS users with current and former TCIGS smokers serving as comparative groups. These studies will provide a comprehensive view of the physiologic impact of ECIGS, and will assess whether either or both airway tissues can be used to readily assess the physiological effects of ECIGS exposure. The third study will evaluate the effect of ECIGS exposure in two in vitro model systems. One model recapitulates the physiology of the airway by growing primary airway epithelial cells in organotypic culture; while the other uses genetically modified airway epithelial cells that are sensitized to undergo carcinogenic transformation. These models will allow us to use gene expression to evaluate the fidelity of the response to in vitro exposure, and rapidly test the effects of ECIGS exposure in promoting carcinogenesis. Successful completion of these aims using ECIGS will set the stage for using these approaches with a variety of other tobacco products and will alter the paradigm for evaluation of new tobacco products, enabling rapid assessment of their potential health risks and carcinogenicity. PUBLIC HEALTH RELEVANCE: There is an urgent need to rapidly assess the physiologic impact of new tobacco products to identify those that pose serious health risks. We are developing a system to evaluate such products based on detailed molecular portraits of how they impact the biology of airway cells from users of these products and comparing this to how cells grown in the laboratory respond to exposures to these products to determine the feasibility of rapid lab-based product assessment. As our test case, we will study E- cigarettes: an inhaled nicotine delivery device that has been used by over 3% of the adult US population despite a paucity of data about their safety and long term health impact.